During a speech in Brussels on 25 April, singer Bjorn Ulvaeus, 72, revealed that virtual "Abbatars" are being created to represent the four members of the pop group of the upcoming digital tour, expected for 2019 or 2020.

They will be pictured as they looked during the height of their fame, with Ulvaeus saying: "We thought we looked good that year."

"Apparently a cranium doesn't change with age the way the rest of your body falls apart." ABBA have sold more than 400m albums but have not performed since 1986, other than a brief appearance at a private party in 2016.